We live on a shallow well near the bay on the Central Oregon coast, and we get a lot of surface water and other contaminants from the local ground water, because of how shallow it is. Coliform is a problem. I have no problems with nitrates, arsenic or anything else, just coliform. After shocking the well just once with this product, the water came back from the lab showing no presence of coliform after 7 days. I plan on shocking it on a regular basis (quarterly if necessary). It comes with pellets for the bottom of the well, and granules (rinses the upper well wall areas) that you mix with water and make a slurry that you then pour down the well access port. Very easy to do. Just ensure you follow instructions on the package.
Rating: [4 of 5 Stars!]